How to Set Up Rigid Body Physics in Blender

Setting up a basic rigid body physics simulation in Blender allows you to create realistic interactions between solid objects, such as falling blocks, colliding spheres, or tumbling debris. This guide provides a straightforward, step-by-step walkthrough of the entire process, from preparing your 3D models and applying active or passive physics properties, to configuring collision shapes and playing back your simulation.

Step 1: Prepare Your 3D Scene

Before applying physics, you need at least two objects in your scene: an object that falls or moves (the active object) and an object for it to land on (the passive ground plane).

  1. Open Blender and start with a new default scene.
  2. Use the default Cube as your falling object. Position it slightly above the grid by pressing G then Z and moving your mouse upward.
  3. Add a ground plane by pressing Shift + A, navigating to Mesh, and selecting Plane.
  4. Scale the plane up by pressing S, typing 10, and pressing Enter.

Step 2: Assign Rigid Body Settings to the Ground (Passive Object)

The ground needs to act as a solid barrier that does not move when gravity is applied.

  1. Select the Plane in your viewport.
  2. Navigate to the Properties Panel on the right side of the screen and click on the Physics Properties tab (represented by a circular icon with an orbiting dot).
  3. Click the Rigid Body button.
  4. In the settings that appear, change the Type from Active to Passive. This ensures the ground remains stationary during the simulation.

Step 3: Assign Rigid Body Settings to the Cube (Active Object)

The cube needs to react to gravity and collide with the ground plane.

  1. Select the Cube in your viewport.
  2. In the Physics Properties tab, click the Rigid Body button.
  3. Keep the Type set to Active. Active objects are fully controlled by the physics engine.
  4. Leave the Mass at the default 1.0 kg for now.

Step 4: Configure Collision Shapes

To ensure accurate collisions and prevent objects from clipping through each other, you must define their collision boundaries.

  1. With the Cube selected, look at the Settings section under the Rigid Body panel.
  2. Locate the Shape dropdown. For a standard cube, Box is the most computationally efficient and accurate setting.
  3. Select the Plane and ensure its collision shape is set to Convex Hull or Mesh to ensure the cube registers the flat surface accurately.

Step 5: Run and Refine the Simulation

Now that the physics properties are assigned, you can test the animation.

  1. Go to the timeline at the bottom of the screen and ensure the playhead is at Frame 1.
  2. Press the Spacebar to play the animation. You will see the cube fall under the influence of gravity and land on the plane.
  3. To adjust physical behavior, select the cube and modify the Friction (how much objects slide) or Bounciness settings under the Surface Response dropdown in the Physics Properties tab.

Step 6: Bake the Physics Simulation (Optional)

Once you are satisfied with the movement, you should bake the simulation to lock the physics calculations into keyframes for rendering.

  1. Go to the Scene Properties tab (represented by a cone, sphere, and light icon).
  2. Expand the Rigid Body World section.
  3. Expand the Cache subsection.
  4. Click Bake. Blender will calculate the entire physics sequence, allowing you to scrub through the timeline smoothly.